The present invention relates generally to a unit for packaging a product, particularly a cosmetic product which may, for example, be in the form of a spray or of a foam or mousse, and for dispensing it under pressure. More particularly, the invention relates to devices of the type having a propellant kept separate from the product that is to be dispensed, for example, via a flexible-walled pouch or a moving piston.
In the field of cosmetics, certain products, particularly those to be dispensed in the form of a spray or of a foam or mousse, contain a liquefied gas. With such products, it is sometimes necessary to package them separately from the propellant intended to keep them under pressure. To do this, the product may be packaged in a flexible-walled pouch in communication with a valve, which is generally surmounted by a push-button for actuating the valve. The propellant gas is packaged in a volume formed between the exterior surface of the pouch and the interior wall of an outer body, generally of cylindrical shape. This volume is filled with propellant gas via a filling valve generally arranged in the bottom of the outer body.
Alternatively, the product is kept separate from the propellant gas by means of a piston capable of sliding in sealed contact against the interior surface of the body of the device. The piston can be introduced into the device via an attached bottom of the outer body.
In order to obtain the desired xe2x80x9ccrushingxe2x80x9d of the pouch, by collapsing its walls, or to obtain the required advance of the piston, such a system requires that throughout the life of the device, that is to say from first use to last use, the pressure exerted by the propellant be higher than the vapor pressure of the product. The opposite situation could lead to pouch inflation, which could go so far as to burst the pouch, or to force the piston backwards inside the cylindrical body.
A first solution might entail using a compressed gas by way of propellant. In order to have sufficient pressure at the end of use of the device, this solution would necessitate a very high initial pressure, which might be incompatible with legislation in this field. Furthermore, in the case of a container made of thermoplastic material, the variation in pressure which would be generated between the first use and the last use would be prejudicial to the overall performance of the device.
Another potential solution might involve using a liquefied gas as the propellant, for example, a butane, a propane, or a dimethyl ether. A liquefied gas is a gas which includes both a liquid phase and a vapor phase above the liquid phase. This solution, although satisfactory from the point of view of the pressurization it allows, is not without its drawbacks. Specifically, when the outer body of the device is translucent or transparent, enabling one to see how much product is left to be used, consumers see liquid xe2x80x9cwanderingxe2x80x9dfreely in the volume between the flexible pouch and the outer body of the device. This is perceived in a negative light by consumers who imagine that the pouch is not entirely leak-tight and/or that they will not be able to use up all of the product they have purchased.
U.S. Pat. No. 5,256,400 describes a dispensing apparatus including a polymeric material having an array of pores in which a compressed gas, dissolved in a solvent, is trapped, so as to increase the amount of compressed gas that can be placed in the container that is to be pressurized.
EP-A 0 569 590 discloses dissolving a compressed gas in a sorption agent so as to increase the amount of compressed gas that can be placed in a container that is to be pressurized.
According to one aspect of the invention, a device for dispensing a product includes a container having an interior including a first compartment and a second compartment. The first and second compartments are separated from one another in a sealed manner. At least part of the container is either translucent or transparent.
The first compartment of the dispensing device contains a product and is in communication with a valve. The second compartment is provided with a propellant having a gaseous phase and a liquid phase. In addition, the second compartment includes a retainer configured to trap the liquid phase of the propellant. At least a portion of the retainer is permeable to the gaseous phase of the propellant.
Preferably, the liquid phase of the propellant gas is retained inside the retainer so that it is not possible to see liquid in the free state through the transparent or translucent part (i.e., walls) of the container. The consumer, looking through the transparent or translucent walls, preferably sees only the first compartment which is arranged inside the container and whose volume diminishes with use.
In addition, in the liquefied state, a single drop of gas may be enough to pressurize the container, which limits the drawbacks affecting the environment and associated with the use of certain xe2x80x9charmfulxe2x80x9d gases, the drawbacks of which are recalled in U.S. Pat. No. 5,256,400 discussed hereinabove.
Furthermore, there may be limited contact between the liquid phase and the means separating the two compartments, whether this be a flexible-walled pouch or a moving piston. Likewise, contact between the liquid phase of the propellant and the body of the container may be mainly in the zone facing the retainer. This may reduce the risk of degradation of the materials used in such devices, particularly the materials for producing the means separating the two compartments in sealed fashion.
The propellant may be a hydrocarbon, for example, a butane, a propane, a chlorofluorocarbon (CFC), a fluorocarbon, or a dimethyl ether.
According to a first preferred embodiment, the first compartment is delimited by a flexible-walled pouch. A pouch such as this may be made of a complex which may include a layer of metal, for example, aluminum, and at least one layer of a thermoplastic, for example, a polyamide, polyethylene, or polypropylene. The walls of the pouch can collapse with successive dispensing operations under the effect of the pressure obtained outside the pouch.
Alternatively, the first compartment may be separated from the second compartment in a sealed fashion by a moving piston. The piston is able to slide in sealed contact against the interior surface of the container, thus delimiting an upper volume containing the product that is to be dispensed and a lower volume containing the propellant gas.
In one preferred embodiment, the container is of cylindrical or spherical shape. In another preferred embodiment, the retainer is placed in the bottom of the container.
The retainer may be immobilized inside the container by a stop. Alternatively, the retainer may be bonded or welded into the second compartment. Other means of attachment may also be envisaged.
The retainer may be formed of a block of open-cell or semi-open-cell foam, of a felt, of a porous membrane located some distance from the bottom of the container, or of a sintered material. By way of example, use is made of a polyurethane foam of the type marketed by the company RECTICEL(copyright) under the reference POTTSCORER 430(copyright). Also by way of example, the retainer may be made of silicone. The configuration of the retainer, for example, its dimensions and/or its absorption characteristics, are chosen to suit the maximum volume of liquid that it is to contain. Preferably, complete saturation of the retainer is avoided, because this may significantly reduce its ability to actually retain the liquid it contains.
The outer container may be made of thermoplastic. By way of example, use may be made of a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN), a polybutadiene (PBT), or a blend of such thermoplastics.
In a preferred embodiment, the product placed inside the first compartment may contain a liquefied gas, so that when dispensed via the valve the product forms a foam or mousse, a gel, a cream, for example, a care cream, a milk, or a spray. By way of example, the product may be a shaving foam, a deodorant spray, a care cream, or a hair care product, for example, a hairspray, a lacquer, or a hair styling mousse.
Another aspect of the invention provides a method of dispensing a product to a surface region, for example, an external body portion. The external body portion may include hair, skin, a combination of hair and skin, and the like. The method includes providing the dispensing device, actuating a valve to dispense product from the device, and directing the dispensed product to a surface region. Preferably, the product is hair care product, skin care product, or other cosmetic product.
Apart from the provisions explained hereinabove, the invention may include a certain number of other arrangements which will be dealt with more fully hereinafter with regard to some embodiments which are described with reference to the drawings appended hereto, but which are not in any way limiting. It is to be understood that both the foregoing description and the following description are exemplary, and are intended to provide further explanation of the invention as claimed.